1. Field of the Invention
This invention relates to an electrical system consisting of individual subassemblies, particularly to a control system which is composed of modules, wherein the individual subassemblies comprise housings, which are adapted to be arranged in a row and are provided with plug terminals for counterplug terminals on a subassembly carrier for making electrical line connections. The housings are secured to the subassembly carrier by detachable retaining means, particularly by swivel holders which permit the housings to be swung up, and by snap holders for locking the housings when they have been swung into the row.
The design of an electrical system composed of individual subassemblies permits systems which differ in size or serve different purposes to be assembled from subassemblies which are identical or similar at least in appearance and in dependence on the size of the system and the space which is available it is possible to superimpose a plurality of rows of subassemblies and the line connections between the rows may then be effected by interposed busbars or cables.
2. Description of the Prior Art
DE-U1-84 15 458 discloses a system of the kind described first hereinbefore. In that known system the subassembly carrier consists of a profiled rear wall plate, which extends over the height of the housings of the subassemblies and extends continuously throughout the length of the row, and the housing of each subassembly can be secured to said plate. The housings are preferably provided at the bottom with hooks, which are swung into profiled troughs formed in the rear wall, and the housings are secured at the top by separate retaining members, which separate adjacent subassemblies and are mounted on retaining rails which are integral with and protrude from the carrying plate. The electric supply lines, ground lines and preferably also the data lines consist of lines which extend throughout the length of the plate and near the terminals of the several subassemblies are provided with counterplug assemblies for plug terminals which protrude from the subassemblies. In control systems the data lines preferably consist of so-called bus lines.
The known design has the disadvantage that the plug terminals must be mounted on the subassembly carrier in accordance with the subassemblies which may differ in width and the sequence of the subassembly carriers which differ in width must be determined in advance. Besides, the continuous rear wall plate is an expensive part, which must be cut or made in dependence on the length which is required for the row. Finally, subassemblies differing in width will require the making of separate housings, which differ in width and fit the subassemblies. Even housings having the same width may differ in their basic structure in dependence on the intended use of each housing. For this reason it will be necessary for the manufacture only of the subassembly carrier and of the subassembly housings for such system to provide a large number of different molds for making the subassembly carriers and housings, which in most cases are made of plastic. Besides, any extension or alteration of an existing system will require the overall design to be altered and will require in most cases an alteration of the baseplate which constitutes the subassembly carrier and of the wiring and plug arrangement on such plate and will require a removal of all or at least most of the existing subassemblies. For this reason such alterations or extensions will take a long time and will require the entire system to be shut down for a correspondingly long time. A replacement of individual subassemblies for repairs or alterations will not be possible unless an exactly fitting replacement part for said subassemblies is available.
In other known systems, such as are known from DE-U1-86 26 971, the individual subassemblies are accommodated in closed housings, which by means of a snap lock on their rear side can be mounted on a profiled carrying rail, such as a hat profile rail, so that the housings are juxtaposed in a row. In that case housings which differ in width may be assembled in rows having any desired length. A disadvantage resides in that an electric line connection to system parts accommodated in the housings will normally have to be made by means of cables extending from housing to housing so that a permanent wiring will be required and a replacement of individual elements or subassemblies will require a shutdown of the system and a higher assembling expenditure.